Electrostatic influence-machine.



PATENTED JAN. 9, 1906.

E. THOMSON. y l ELEGTNOSTATIG INFLUENCE MACHINE.

APPLICATION FILED JUNE 23,1904.

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E. THOMSON. ELEGTROSTATIC INFLUENCE MAGHNE.

APPLICATION FILED JUNE 23,1904.

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UNITED STATES PTENT OEEIOE.

ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTROSTATIC INFLUENCE-MACHINE.

Specification of Letters Patent.

Patented Jan. 9, 1906.

l`mplication filed .Tune 23, 1904. Serial No. 213,780.

To a/ZZ whom, t may concern;

Be it known that I, ELIHU THOMSON, a citizen of the United States,residing at Swampscott, county of Essex, State of Massachusetts, haveinvented certain new and useful Improvements in Electrostatic Iniiuence-Machines, of which the following is a specification.

This invention relates to static electricitymachines 5 and its object isto provide an electrostatic influence-machine having in its revolvingparts the minimum diameter of insulating material, but so disposed thatit can be made massive and strong.

A further object is to simplify the structure of the stationary partsand reduce as far as possible the thickness of the dielectric throughwhich the inductive action is produced.

The machine is particularly adapted to the production of moderatepotentials and is also capable of being run at a high speed, so as toincrease the output. l,

The invention consists in certain features of construction hereinafterset forth, and pointed out in the claims.

`In the accompanying drawings, Figure 1 is a front elevation of amachine embodying my invention. Fig. 2 is a top plan view of the same.Fig. 3 is a detail elevation of a brush and its holder. Fig. 4 is an endelevation of the machine. Fig. 5 is a vertical cross-section through theshaft. Fig. 6 is a detail front elevation, and Fig. 7 a longitudinalsection, of one of the vanes. Fig. 8 is an end view of a modifiedconstruction, and Fig. 9 is a front elevation of the same.

Referring first to Figs. 1 to 7, the frame of the machine is composed ofduplicate castings meeting on a median plane and suitably fastenedtogether. The frame comprises a base 1, from which rise two parallelcolumns 2, connected at the top by a cross-bar 3 and at about theircenters by two outwardlycurved horizontal brackets 4, one on each sideof the vertical plane of the columns and both lying in the samehorizontal plane. In each bracket is a bearing for a horizontal shaft 5,which extends perpendicular to the vertical plane of the columns.Carried upon and driven by this shaft is a disk 6, of insulatingmaterial, such as hard rubber, to the edge ofl which are securedradiating wings or vanes 7, sector-shaped with rounded corners. Thesevanes are preferably made of aluminium for the sake of lightness and arefastened to the front face of the disk 6, which may be made thick andmassive enough to be amply strong. Sleeved upon the front portion of theshaft is a rotatable quill 8, on which is secured a disk 9 of insulationsimilar to the disk 6 and simi- -larly provided with aluminium vanes 10.The number of vanes on the two disks may be the same or different, asdesired. Means are provided for revolving the two sets of vanes inopposite directions, preferably consisting of a friction-disk 11 on theshaft driving a friction-disk 12 on the quill through one or moreintermediate stationary friction rolls 13, journaled on studs fixed inthe front bracket. The friction-disk 11 may also serve as the maindriving-pulley of the machine. The friction-disk' 12 is preferably notrigidly secured to the quill, but is splined thereon and provided with acompression-spring 14 for keeping it pressed against the rolls 13. Itwill be seen that a belt upon the pulley 1.1 will rotate the shaft andthe vanes 7 in one direction, while the friction-rolls will cause thedisk 12 and the vanes 10 to revolve in the opposite direction.Arrangement is made whereby as the vanes revolve they come in electricalcontact with stationary brushes carried on the frame of the machine andconnected together or grounded. To this end each vane has a sort ofcommutator segment or extension on thc edge of its supporting-disk,preferably a small screw 15, inserted into the disk, the head of whichtouches the vane and lies flush with the outer periphery of the disk.Upon this periphery bears a pair of spring-brushes 16 17, one paircarried by the rear bracket for the disk 6 and the other carried by thefront bracket for the disk 9. The brushes in each pair are preferablydirected in the direction of rotation of their disk, and their length issuflicient for them to make contact with the disk at diametricallyopposite points. The arrangement is such that the line joining one pairof brushes is substantially perpendicular to that oining the other pair,as clearly shown in Fig. 1. A pointed wire 1S is fixed in the base 1 andprojects up between the two sets of revolving vanes. A similar pointedwire 19 is supported on the cross-bar 3, projecting down into the spacebetween the vanes opposite to the wire 1S. The

cross-bar is made of insulation, such as hard rubber or paraflined wood,so that the two wires 18 and 19 are not electrically connect ed.Fastened to the top of one of thecol- IOO umns is a terminal 20, whilethe wire 19 is carried by a metallic collar 21, on which is mounted asleeve 22, in which slides a terminal 23 to cooperate with the terminal20. When the vanes are revolved in opposite directions, the machinebecomes electrostatically charged and delivers high-tension electricityto the terminal 23, the maximum tension obtainable being governed by theleakages and by the distance apart of the several vanes in each set.

The machine will operate with merely an air-space between the two setsof vanes; but as air is a poor dielectric so far as resistance to sparksis concerned it is best to provide between the sets of vanes a layer ordiaphragm of good dielectric, which occupies nearly all the availablespace. Hard rubber may be used; but I prefer glass or built-up mica. Asingle plate may be used, if desired, with an opening at the center forthe passage of the shaft and openings at the top and bottom for thewires 18 and 19; but as there is no especial advantage in this I find itsimpler to employ two pieces 24 24, having approximately the form ofhalf-octagons or semicircles, supported at their. edges by grooves 'inthe frame, where they can be either cemented in place or embedded infelt or otherwise secured. Their adjacent edges are spaced apart to letthe shaft pass through and also to give space for the collectors 18 and19.

The operation of the machine is very much the same as that of thewell-known Wimhurst machine, except that owing to the absence ofrotating plates of dielectric a very much higher speed may be sustained,especially as the disks 6 and 9 may be made as thick and strong asdesired.

While it is desirable to have the brushes make a firm contact with thevanes at the start, this contact may be almost or wholly removed afterthe machine is running and charged. This effect may be accomplished bythe device shown in Fig. 3, where the spring 25 causes the lugs 26 onthe looselypivoted handle 27 to abut against the pins 28, and thuseither hold the brush down upon the disk or on passing the center itwill pull the brush-carrier 29 against a stop 30, and thus relieve thepressure on the brush.

The machine shown in Figs. 8 and 9 has both collectors 18 and 19supported on insulating cross-bars 3 and 31. Either or both of theterminals 32 33 may be used for obtaining the output.

l/Vhat I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. An electrostatic influence-machine, coinprising two sets ofvanes-revolving in parallel planes but in opposite directions, andstationary collectors projecting into the space between the two sets.

. said disks in opposite directions.

5, An electrostatic influence-machine, comprising a shaft, a strong diskof insulation. secured thereon, a quill sleeved on said shaft andcarrying a second disk of insulation, radiating metallic vancs on .cachdisk, and gearing connecting said shaft and quill to cause them torotate in opposite directions.

6. In an electrostatic iniiuence-machine, the combination with twostrong disks of insulation, of metallic vanes radiating therefrom andhaving metallic extensions on thc peripheries thereof, and brushestouching said peripheries at diametrically opposite points.

7. In an electrostatic influence-machine, the combination with two setsof insulated metallic vanes revolving in opposite directions, oft\\fo"collectors located at opposite points between said sets, and twopairs of grounded brushes for touching the outside of said vanes `justbefore they pass the collectors.

8. In an electrostatic influence-machine, a frame composed of a base,columns and. horizontal brackets connecting said columns, said framebeing cast in integral similar halves.

9. In an electrostatic influence-machine, the combination with a framecomprising a base, columns, connecting-brackets and a cross-bar, of twoplates of dielectric secured in said frame with aispace between theiradjacent edges.

10. In an electrostatic influence-machine, the combination with astationary dielectric diaphragm, of two sets of insulated vanes rotatingin opposite directions on opposite sides of the same, collectorsprojecting between the sets in an opening in said diaphragm, and twogrounded brushes for each set adapted to touch the outside of said vanosjust before they reach the collectors.

In witness whereof I have hereunto set my hand this 21st day of June,1904-.

ELII-IU THOMSON.

Witnesses:

DUGALD MCK. MCKILLOP, HENRY O. WESTENDARP.

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